Extra-corporeal blood circulation



United States Patent i 13,s33,40s

[72} Inventor Jean-Marc Paoli 16 Traverse de Pomeques Le Chateau,Marseille, France [21] Appl. No. 539,261 [22] Filed March 30, 1966 [45]Patented Oct. 13, 1970 [32] Priority March 31, 1965 [33] France [3120,948

Pat. 1,451,277

[54] EXTRA-CORPOREAL BLOOD CIRCULATION 5 Claims, 8 Drawing Figs.

[52] U.S.Cl 128/214, 23/2585 [51] 1nt.Cl A61m 5/00 [50] Field ofSearch128/214, 214.2, 1 H-L Digest: 23/2585: l37/(lnquired): l03/(lnquired)[56] References Cited UNITED STATES PATENTS 2,927,582 3/1960 Berkman etal 23/2585 3,142,296 7/1964 Love 23/2585 OTHER REFERENCES Surgery, vol.45 #2 2/59. pp. 288-291 (Dickson et a1.) l28/H-L. Dig.

Murphy-Amer. Soc. Art. Inter. Organs, 1961, vol. 7 pp. 361-68, l28/H-L.Dig.

Primary E.talniner-Dalt0n L. Truluck Attorney-William Anthony DruckerABSTRACT: In an extra-corporeal blood circulating system synchronisedwith the cardiac cycle, an electronic unit including a multitrackelectrocardiograph receiving an R wave from a patient and convertingsaid wave into a QRS output signal; an arterial line and a venous line,a return reservoir connected to said lines; a continuous delivery pumpcon nected in said arterial line; a shunt connecting said arterial lineto said reservoir for branching off said pump at the moment of cardiacsystole, a valve for opening and closing said shunt; a control systemfor governing said valve, said control system including a piston meansresponsive to said output signal to pinch or release said shunt insynchronism therewith.

OXYGENATING DEV/CE Patented Oct. 13, 1970 3,533,408

r 1 23:: E SORT/N6 v ECG osczuosco I 23 'j' i:

TACHYMET Y Y A i 24 e m MONITOR/N6 E D SIGNAL OSCILLOSCOPE I l I g 3/ g27 MAGNETIC PACE MAKER RECORDER JEn/v-mm FQOL/ EXTRA-CORPOREAL BLOODCIRCULATION This invention relates to an apparatus for extra-corporealblood circulation in synchronism with the cardiac cycle.

It is known that any extra-corporeal circulation of the blood(hereinafter abbreviated to E.C.C.), carried out, for example, before orduring or after a surgical operation, comprises an apparatus whichincludes:

an arterial return path or arterial line;

a venous return route or venous line;

an intermediate circuit between these two (with a reservoir or oxygenappliance); and

a pump for arterial injection.

Arterial injection is generally carried out in a continuous manner. Whensuch injection is used it may add its pressure to that of the bloodpumped by the heart, and may thereby cause such discomfort to thepatient that it cannot be endured very long.

To avoid such discomfort it is present practice to use blood pumpsoperating for short periods of time and triggered by anelectrocardiograph during the diastolic phase of the cardiac cycle.

However, such pumps operate with a certain time lag which increases withthe flow, and tends to limit the flow. They also inject rapidly apredetermined volume of blood, which in the case of variations of thecardiac cycle, may be too large or too small.

To remedy this, the object of the present invention is to provide acontinuous-flow blood pump which is only branched off, at the moment ofthe cardiac systole (cardiac contraction) by a shunt connecting thearterial line to the intermediatecircuit, e.g. to the return reservoir;this shunt includes a valve the opening and closing of which iscontrolled, at suitable moments and after predetermined durations, by anelectric unit which utilizes the QRS signal of an electrocardiographapparatus, thus itself regulating the moments and durations'of arterialpipe 16 connecting the patients artery to the pipes 13 the opening andclosing actions, or enabling them-to be regulated, in accordance withthe desired result.

The device can be connected to any surgical E.C.C. as a preoperatorymeasure, or at the end of the operation, or to afford medical treatment.

In the accompanying drawing,

FIG. I is a graph showing relative time periods and durations;

FIG. 2 is a graph showing a modification of the time periods anddurations;

FIG. 3 is a diagram which shows the apparatus in actual use connected toa patient;

FIGS. 4 and 5 show two different modes of use of a shunt system in thedevice;

FIG. 6 shows schematically a preferred construction of shunt valve;

FIG 7 is a block diagram of an electronic control device;

FIG. 8 is a block diagram showing a monitoring system for the controldevice.

FIG. 3 shows the device of the invention, as applied to a patientprepared for a surgical operation such as open heart surgery, or duringor after the latter. An electronic synchronizing unit 10 receives the Rwave of the patient from an ECG or pace maker" (not shown) and convertsit into a signal of which the duration is regulated as desired. Thisoutput signal is received by an electromechanical bypass control 11 forcontrolling the closing and opening of a valve 12 in a shunt pipe 13.The shunt 13 which short circuits the pump, thus rendering possible anarterial return", which is facilitated by gravity, towards theintermediate circuit, and hence towards a return reservoir; this shuntcan be a tube of elastic material such as Tygon.

The valve 12 is mounted on said shunt pipe 13 and can be rapidlyactuated for example by an electric solenoid valve as described inrelation to FIG. 6, to compress the pipe I3. In FIG. 3 the valve 12 isshown open. The shunt pipe I3'leads to an oxygenating apparatus 14,which forms a return reservoir. In parallel with the shunt pipe 13 thereis a continuousdelivery pump-l5 connected to the reservoir 14. A similarand 15. The valve 12' is mounted on the arterial pipe I6 before itsconfluence with the shunt pipe I3 in order to enable its return deliveryto be reduced, if necessary, in synchronism with the shunt valve I2,during the shunting process; similarly, 1

other valves of the same type can be mounted at other points on the ECCcircuit. A venous pipe 17 connects the apparatus 14 to a vein, and

in FIG. 3 is shown without any valve in it.

In FIG. 4 there is shown diastolic transfusion. The shunt 13 is closedby closing the valve I2, and the arterial pipe 16 isleft open at valve12' (that part of the shunt 13 which follows the closure at 12 beingshown in broken line).

In FIG. 5 there is shown systolic by-passing by the shunt pipe 13, andthe two valves 12 and 12' are left open; it is thus possible to permitan arterial return to take place, through the pipe line 16, or tointerrupt it, by operating the valve I2.

FIG. 6 shows, schematically, a form of control valve for the shunt'pipe13 or for any other flexible pipe. The pipe l3is clamped diametricallybetween a fixed part 18 and a movable part 19, the latter beingcontrolled by a piston 20 connected to a solenoid valve 21 which in itsturn is controlled by an electric line 21 "from the control unit 11.

FIG. 7 shows the structure of the electronic synchronizing unit 10,which includes an ECG unit 22, and its connection to the control deviceI l for the valve 12 of the shunt pipe 13 and this diagram provides anexplanation of the application of the systole-diastole selectioncircuit, and of the regulating system.

The electronic unit I0, which enables the opening otlthe shunt pipe 13to be regulated at the exact moment when the systole of cardiaccontraction takes place, also enables the satisfactory operation of theassembly used to be verified; this electronic unit analyses theelectrocardiographic complex and enables pressure control to beeffected, for the purpose of the aforementioned regulation.

This electronic unit includes Y a. The multitrack electrocardiographicapparatus 22 '(abbreviated to "ECG), with oscilloscopes 29 and 30enabling the most suitable electrocardiographic track to be selected atany moment.

b. The cardiotachymeter 23 imparting a brief impulse at the moment whenthe QRS signal of the ECG occurs, upon reception of R waves from thepatient;

c. The relay 24 by which this short impulse is converted into arectangular impulse of which the duration can be regulated as desiredand by which the shunt tap will be "controlled.

d. The relay 25 supplying a required advance in relation to the originalQRS wave, at the moment when the shunt pipe valve opens, and capable ofbeing coordinated with the frequency of the heart beats.

e. The pace maker 27 which takes over when no waves are received fromthe patient, and the relay 26 for actuating f. A filtering relay'(notshown).

g. Electronic manometers for arterial and venous observation (notshown). t

h. A second oscilloscope 30 for monitoring and regulation,

which enables any possible regulating actions to becarried out and onthe screen of which the following are recorded: the ECG track retained;the signal of each relay; an arterial pressure track; a venous pressuretrack; and the signal relating to the opening or the closingof .theshunt tap; 1

i. an audiosignal; and j. a multitrack magnetic recorder. FIG. 8provides an explanation of the visual monitoring system. f

For the systole-diastole selection circuit (FIG. 7) in the ECG unit 22one of the ECG tracks is selected. a cardiotachymeter 23 takes theinstantaneous impulses from the positive ECG deflections on thisselected track; a relay 24 receiving the output of the cardiotachymeter23 then effects a filtering operation, so that only a QRS impulse 11remains and this is fed to a relay 25 which converts it into arectangular impulse of duration 12". This is fed to a relay 26 of a pacemaker 27 and simultaneously to the bypass control device ii' 'iiWlficnBp'eE'sYhE s'h'um i3 au'rirgtra'szaba 12'.

For monitoring (FIG. 8):

Signals from the ECG 22 are fed to a sorting oscilloscope 29 receivingall the tracks, and from there any selected signal can be transferred toa monitor tube 30 showing for example one ECG track, one track for relay24, one arterial pressure track, one track for relay 25, one venouspressure track, opening or closing signal of electromechanical selector11-12. At the relay stage 24 there is regulation of the duration :1; atthe relay stage 25, there is regulation of the duration 12 (time forwhich the shunt pipe 13 is open, and duration of systole), starting ofthe electromechanical control lIl2, regulation of venous returndelivery" and of arterial return and regulation of the pump.

An audio signal is obtained from an audio unit 28; control oscilloscope30: unit 31 is a multitrack magnetic recording system.

Referring to FIG. I, it is shown how, staning from a QRS signaL'there isobtained a long impulse 4 for the control of the shunt valve 12.

On the arterial pressure PA, the point PS indicates theclosing of theaortic sigmoid valvulae.

In the P.QRS-T complex, point P indicates the contraction of theauricles of the heart, QRS indicates the wave marking the commencementof the contraction of the ventricles. and T indicates the depolarizationwave.

The original impulse I, which is short, and synchronous with QRS, istaken up by the the cardiotachymeter 23. If it is accompanied by aparasitic impulse 2 caused, for example, by T, filtering is appliedduring the period 4 and interrupts this parasitic impulse. At 5, thesignal of the opening and closing relay occurs, the shunt pipe I3 beingopen during the hatched period 6, which can be increased in accordancewith the arterial pressure curve PA. The arrow 7 indicates the instantof opening and the arrow 8 the instant of closing.

FIG. 2 shows an alternative version of part 5 of FIG. 1, the openingtaking place with a certain advance (the arrow 9 indicating the opening,advanced in respect of the arrow 7 or the arrow QRS shown afterwards,with the hatched opening period 6 The apparatus is utilized as follows:

The signals of the ECG unit 22 are transmitted to its sortingoscilloscope 29, on which they can be compared in order to select thebest track or signal. The QRS signal retained is analysed by thecardiotachymeter 23, after the regulation of the threshold in accordancewith its amplitude. We thus obtain an impulse on the QRS signal.

But if positive deflections of the same amplitude (as shown at T, forexample, FIG. 1) are received from the cardiographic system, filteringmay be required. The first signal actuates the electronic relay 24 whichinterrupts the cardiotachymeter circuit for a period corresponding tothe duration of the electrocardiographic complex following the originalsignal. It is thus the first signal that is transmitted (and not thesubsequent signal, e.g. that emanating from T). At the end of thisperiod, the relay 24 returns the cardiotachymeter 23 to the circuit, andthe first signal of the following complex may set up an original impulseand block the cardiotachymeter. The satisfactory operation of thisfiltering system is verified on the screen on the monitoringoscilloscope 30. A synchronous visual signal is recorded below theelectrocardiographic track and enables this period to be prolonged orshortened at any moment.

This original impulse. thus filtered, sets up an audiosignal, in unit28, which enables the electrocardiographic rhythm to beconstantlymonitored by ear and makes it possible to take immediate action in theevent ofdisturbance.

The original impulse is transmitted tothe electronic relay 25 whichconverts it into an impulse whose duration can be regulated as desired;this duration must correspond to the time for which the valve 12 of theshunt pipe 13 is open, which time is steplessly variable, e.g. betweenzero and a quarter of a second or more. This impulse is verified on themonitoring oscilloscope 30 by a synchronous visual signal in thevicinity of the arterial pressure track". It is thus known at any momentwhether the opening of the shunt valve 12 is being correctly controlled.In this case, the final order can be transmitted to the said shunt valve12 and to the valve 12', if provided on the arterial line. It alsocauses a signal to be conveyed to the screen of the monitoringoscilloscope 30, so that the periods during which the valve has beenactually operated can be accurately differentiated in the recordings.

The final regulating operations are carried out in accordance with thehaemodynamic effects desired. They necessitate control of thecommencement of the venous return (the degree of shutting of the valvebeing variable by an electrical or manual control means), of thesystolic arterial return, and of the real injection delivery whichdepends on the output of the injection pump (ascertainable from therevolution-counter on its control panel), and of the through flow in theshunt pipe as determined by the frequency and duration of opening ofvalve control, and the flow cross section of the pipe.

After adjustment of the electronic unit, and with the ECC progressingunder normal conditions, the shunt valve 12 is actuated, the relay 25being closed and then progressively opened for oscilloscopicverification of the pressure curves so as to obtain the value which isdesired from the haemodynamic point of view.

The apparatus enables the arterial and venous outputs to be distributedin such a way as to enable any one of the following to be obtained,according to the type of return selected:

1. A veno-arterial ECC with diastolic injection, the artery being closedduring the systole, and the injection continuing to be branched by theshunt pipe (treatment of righthand cavities of heart, necessitating theuse of a blood oxygenating apparatus);

an arterio-arterial ECC with diastolic injection, with an arterialreturn during the systole, the delivery of the pump being branched bythe open shunt pipe, while during the diastole the injection is effectedby closing the shunt pipe (for treatment of left cavities of heart, noblood oxygenating apparatus being necessary here); and

3. an ECC which is any combination of those indicated above, accordingto the relative size of the venous and arterial returns (mixed" oroverall" heart treatment). 1

The invention offers a further advantage in that the opening of theshunt pipe enables ventricular ejections to be facilitated, this beingpartly effected in an open system at a low pressure since it is incommunication with the return reservoir of the ECC. It thus provides atrue cardiac treatment combining the advantages of a reduction of thework having to be performed by the heart, and administration of adiastolic transfusion.

I claim:

1. In an extra-corporeal blood circulating system synchronised with thecardiac cycle, an electronic unit including a multi-trackelectrocardiograph receiving an R wave from a patient and convertingsaid wave into a QRS output signal; an arterial line and a venous line,a return reservoir connected to said lines: a continuous delivery pumpconnected in said arterial line; a shunt connecting said arterial lineto said reservoir for branching off said pump at the moment of cardiacsystole, a valve for opening and closing said shunt; a control systemfor governing said valve said control system including a piston meansresponsive to said output signal to control said shunt in synchronismtherewith.

4. System according to claim 1, wherein said return reservoir consistsof an oxygenating device.

5. System according to claim 1, having a second similar valvecontrolling said arterial line and means for controlling said secondvalve in synchronism or alternation with said first valve.

